1. Field of the Invention
The present invention relates generally to a modification of powertrain control modules in vehicles which utilize passive anti-theft systems, and more specifically to a method of controlling engine starting of a vehicle having a powertrain control module to aid in theft prevention.
2. Description of the Related Art
Automotive vehicles may include passive anti-theft systems which require coding to automatically unlock the vehicle and allow starting of the vehicle. Such passive anti-theft systems have been used in conjunction with powertrain control modules (PCM). The powertrain control modules are utilized to regulate a fuel pulse width to injector drives of fuel injectors. The powertrain control module receives various sensor inputs, including communications via a data link from the passive anti-theft system.
In case of inoperability of the processor of the powertrain control module, an alternate operating strategy mode is provided which is entered during such inoperability to allow fuel to be supplied to the vehicle at a predetermined level. Such mode may be entered by inoperability of the processor of the powertrain control module, which causes the processor to be inoperative and forces the processor into the alternate operating strategy mode.
The fuel pulsewidth used to maintain vehicle driveability in the alternate operating strategy mode is sufficient enough to start the vehicle. While the vehicle is in the alternate operating strategy mode, the fuel pulsewidth used is at a fixed duration, this duration being determined during the development process. This value currently does not change once it has been calibrated to a vehicle/engine family.